Local Drainage Basin Direction is point data used to create directional arrow symbology that depicts the general direction of surface water flow within individual local drainage basins. Particular emphasis is given to directional arrows near the location of local drainage basin outlets. These and similar features along stretches of local drainage basin main stem basins and in coastal basins that drain into Long Island Sound are intended to aid in visualizing the network of local drainage basins in Connecticut. Point features are classified into three types - Outlet Direction, Main Stem Direction and Coastal Direction - and include an attribute that defines arrow direction. Data is compiled at 1:24,000 scale and should only be used for cartographic purposes on maps that also depict Local Drainage Basin Boundaries. Appropriate scale range for viewing is 1:24,000 to 1:80,000.
Refer to the metadata for Local Drainage Basin polygon and line feature classes for additional information on the delineation and use of local drainage basin boundaries.
publication date
Basin Outlet location and direction point features show general locations and flow directions of all Local Drainage Basins in the State of Connecticut. However, some points do not represent locations, and simply show flow direction within local basins. All points are strictly cartographic and locations of all points were chosen to not conflict with other base map features and your ability to read the map. These point features must be symbolized with arrow-like symbols that depict direction based on the numeric values stored in the field named direction angle. (Source: State of Connecticut, Department of Environmental Protection)
Internal feature number. (Source: ESRI)
Feature geometry. (Source: ESRI)
Numeric value representing direction of point, zero degrees points North. (Source: State of Connecticut, Department of Environmental Protection)
Characterizes points as representing main stem flow, outlet direction, or coastal flow direction (Source: State of Connecticut, Department of Environmental Protection)
| Value | Definition |
|---|---|
| Outlet Direction | Point type representing general direction of river or stream towards the local drainage basin outlet. |
| Main Stem Direction | Point type representing the stream direction of main stem local basins. The local drainage basin numbers for Main Stem local basins end with "-00", such as 4302-00 |
| Coastal Direction | Point type representing a very general direction for surface water within local coastal basins. |
Local Drainage Basin Number - Encodes the Local Basin Number for the Direction Point. The Local Drainage Basin Number is the first 2 digits of the 13-digit drainage basin identification number (BASIN_NO). The first digit corresponds to the Major basin number (MBAS_NO). All Regional basins in the same Major basin have the same first digit. A Regional drainage basin number ending in "0" defines the greater main-stem basin for the corresponding Major drainage basin. For example, Regional basin 40 is the main-stem basin for Major basin 4. These main-stem Regional basins are usually named after the corresponding Major basin. (Source: State of Connecticut, Department of Environmental Protection)
Subregional Drainage Basin Number - Encodes the Subregional Basin Number for the Direction Point. The Subregional Drainage Basin Number is the first 4 digits of the 13-digit drainage basin identification number (BASIN_NO). The first digit corresponds to the Major basin number (MBAS_NO) and the first 2 digits represent the Regional basin number (RBAS_NO). All Subregional basins in the same Major and Regional basin have the same first and first 2 digits, respectively. A Subregional drainage basin number ending in "00" defines the main-stem basin for the corresponding Regional drainage basin. For example, Subregional basin 4300 is the main-stem basin for Regional basin 43. These main-stem Subregional basins are usually named after the corresponding Regional basin. (Source: State of Connecticut, Department of Environmental Protection)
Subregional Drainage Basin Name - Text values that correspond to numeric SBAS_NO attribute values. SUBREGION is the English language equivalent of (decodes) the SBAS_NO field. (Source: State of Connecticut, Department of Environmental Protection)
Regional Drainage Basin Number - Encodes the Subregional Basin Number for the Direction Point. The Regional Drainage Basin Number is the first 2 digits of the 13-digit drainage basin identification number (BASIN_NO). The first digit corresponds to the Major basin number (MBAS_NO). All Regional basins in the same Major basin have the same first digit. A Regional drainage basin number ending in "0" defines the greater main-stem basin for the corresponding Major drainage basin. For example, Regional basin 40 is the main-stem basin for Major basin 4. These main-stem Regional basins are usually named after the corresponding Major basin. (Source: State of Connecticut, Department of Environmental Protection)
Regional Drainage Basin Name - Text values that correspond to numeric RBAS_NO attribute values. REGIONAL is the English language equivalent of (decodes) the RBAS_NO field. (Source: State of Connecticut, Department of Environmental Protection)
Major Drainage Basin Number - Encodes the Major Basin Number for the Direction Point. The Major Drainage Basin Number is the first 2 digits of the 13-digit drainage basin identification number (BASIN_NO). The first digit corresponds to the Major basin number (MBAS_NO). All Regional basins in the same Major basin have the same first digit. A Regional drainage basin number ending in "0" defines the greater main-stem basin for the corresponding Major drainage basin. For example, Regional basin 40 is the main-stem basin for Major basin 4. These main-stem Regional basins are usually named after the corresponding Major basin. (Source: State of Connecticut, Department of Environmental Protection)
Major Drainage Basin Name - Text values that correspond to numeric MBAS_NO attribute values. MAJOR is the English language equivalent of (decodes) the MBAS_NO field. (Source: State of Connecticut, Department of Environmental Protection)
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Local Drainage Basin Direction is a cartographic data product. These point feature must be used with Local Drainage Basin polygon and line feature data. They must not be depicted on maps as simple point symbols without symbolizing them with arrows that take on the appropriate direction. Use the DIRECTION_ANGLE and DIRECTION_TYPE attributes to properly classify the features and orient the directional arrow symbols on a map. It is meaningless to use these data without also including local basin boundaries on a map. These data do not represent the exact location of basin outlets or stream confluences. Their position is largely based on the need to locate an arrow symbol near each local basin outlet such that it does not interfere or conflict with the placement of other information typically included on a basin map such as highways, local roads, bridges, waterbodies, political boundaries and geographic names. For this reason, some features may be farther away from the basin outlet than others. This information is not intended to accurately represent the hydrologic connectivity of surface water and were not automatically derived from or based on a hydrologic network such as the U.S. Geological Survey National Hydrography Dataset.
All layers contained in the DEP's base map group layer file, including Lidar 2000 Contours for the state of Connecticut, and Major, Regional, Subregional, and Local Drainage Basins are in GeoDatabase Feature Class format. Lidar Shaded Relief are in Raster Catalog format.
Feature digitizing and attribution (heads up digitizing method) - Using ESRI ArcGIS software, features appearing on the source map were manually digitized on the screen (heads-up digitizing) at a display scale of 1:24,000 using CT DEP's Base Map group layer file, and Lidar 2000 contours displayed in the background for reference. This Base Map group layer included 1:24,000 scale roads, geographic names, and features, waterbodies, and political boundaries. These were used mainly to avoid any conflicting features as these points will be included in maps that contain this information. Individual features were digitized based on information from the Local Drainage Basin database. Features were assigned 'angle' and 'type' attribute values based on information shown in the Basin database.
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Added Attributes - Added and populated the following feature attributes: Major Drainage Basin, Major Drainage Basin number, Regional Drainage Basin, Regional Drainage Basin number, Subregional Drainage Basin, Subregional Drainage Basin number, Direction Angle, In CT, and Direction Type
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Metadata imported.
Dataset copied.
Dataset copied.
Metadata imported.
Dataset copied.
Metadata imported.
The Local Drainage Basin Direction layer retains the feature types and information identified by the State of Connecticut, Department of Environmental Protection and obtained from the Major, Regional, Subregional, and Local Drainage Basin Databases. All attributes have valid values. Attribute values were either entered manually, and express only general information that doesn't need high accuracy, or were populated through a spatial join; and in that case only as accurate as the attribute data in the table it was joined to.
The horizontal accuracy of these data meets the intended use. These data are strictly cartographic. Point feature locations are near and not exactly at the corresponding outlet locations.
The data is complete. There is at least one local basin direction feature for each local drainage basin.
Point features conform to the following topological rules. Points are single part. There are no duplicate points. Points do not overlap. Establishment of logical consistency was performed by the State of Connecticut, Department of Environmental Protection using ESRI ArcGIS software to manually create and control feature topology in geodatabase format. No automated procedures or tests were performed to guarantee desired topology other than visual inspection.
None. No restrictions or legal prerequisites for using the data after access is granted. The data is suitable for use at appropriate scale, and is not intended for maps printed at scales greater that 1:80,000 scale or more detailed than 1:24,000 scale.. Although this data set has been used by the State of Connecticut, Department of Environmental Protection, no warranty, expressed or implied, is made by the State of Connecticut, Department of Environmental Protection as to the accuracy of the data and or related materials. The act of distribution shall not constitute any such warranty, and no responsibility is assumed by the State of Connecticut, Department of Environmental Protection in the use of these data or related materials. The user assumes the entire risk related to the use of these data. Once the data is distributed to the user, modifications made to the data by the user should be noted in the metadata. When printing this data on a map or using it in a software application, analysis, or report, please acknowledge the State of Connecticut, Department of Environmental Protection as the source for this information. For example, include the following data source description when printing this layer on a map: Directional Arrows - From the Local Drainage Basin Direction layer, compiled and published by CT DEP. Source map scale is 1:24,000.
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Although this data set has been used by the State of Connecticut, Department of Environmental Protection, no warranty, expressed or implied, is made by the State of Connecticut, Department of Environmental Protection as to the accuracy of the data and or related materials. The act of distribution shall not constitute any such warranty, and no responsibility is assumed by the State of Connecticut, Department of Environmental Protection in the use of these data or related materials. The user assumes the entire risk related to the use of these data. Once the data is distributed to the user, modifications made to the data by the user should be noted in the metadata.
| Data format: | in format Shapefile, Feature Class (version ArcGIS) |
|---|---|
| Network links: | http://www.ct.gov/deep |
The data distributor does not provide custom GIS analysis or mapping services. Data is available in a standard format and may be converted to other formats, projections, coordinate systems, or selected for specific geographic regions by the party receiving the data.
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